Results of a Direct Search Using Synchrotron Radiation for the Low-Energy (229)Th Nuclear Isomeric Transition

Justin Jeet; Christian Schneider; Scott T Sullivan; Wade G Rellergert; Saed Mirzadeh; A Cassanho; H P Jenssen; Eugene V Tkalya; Eric R Hudson

doi:10.1103/PhysRevLett.114.253001

Results of a Direct Search Using Synchrotron Radiation for the Low-Energy (229)Th Nuclear Isomeric Transition

Phys Rev Lett. 2015 Jun 26;114(25):253001. doi: 10.1103/PhysRevLett.114.253001. Epub 2015 Jun 23.

Authors

Justin Jeet¹, Christian Schneider¹, Scott T Sullivan¹, Wade G Rellergert¹, Saed Mirzadeh², A Cassanho³, H P Jenssen³, Eugene V Tkalya^{4

5}, Eric R Hudson¹

Affiliations

¹ Department of Physics and Astronomy, University of California, Los Angeles, California 90095, USA.
² Nuclear Security and Isotope Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.
³ AC Materials, Inc., 756 Anclote Road, Tarpon Springs, Florida 34689, USA.
⁴ Skobeltsyn Institute of Nuclear Physics, Lomonosov Moscow State University, Leninskie gory, Moscow 119991, Russia.
⁵ Nuclear Safety Institute of Russian Academy of Science, Bol'shaya Tulskaya 52, Moscow 115191, Russia.

PMID: 26197124
DOI: 10.1103/PhysRevLett.114.253001

Abstract

We report the results of a direct search for the (229)Th (I(π)=3/2(+)←5/2(+)) nuclear isomeric transition, performed by exposing (229)Th-doped LiSrAlF(6) crystals to tunable vacuum-ultraviolet synchrotron radiation and observing any resulting fluorescence. We also use existing nuclear physics data to establish a range of possible transition strengths for the isomeric transition. We find no evidence for the thorium nuclear transition between 7.3 eV and 8.8 eV with transition lifetime (1-2) s≲τ≲(2000-5600) s. This measurement excludes roughly half of the favored transition search area and can be used to direct future searches.